Seed dimorphism, chromosome number and karyotype of the amphicarpic species Trifolium argentinense Speg

• Published in: Genetic resources and crop evolution 2010-06, Vol.57 (5), p.727-731
• Main Authors: Conterato, Ionara Fatima, Schifino-Wittmann, Maria Teresa, Dall′Agnol, Miguel
• Format: Article
• Language: English
• Subjects: Agriculture; Amphicarpy; Biomedical and Life Sciences; Chromosome number; Chromosomes; Dimorphism; Flowering; Flowering plants; Flowers; Indigenous species; Karyotype; Karyotypes; Legumes; Life Sciences; Pasture; Plant Genetics and Genomics; Plant Physiology; Plant Sciences; Plant Systematics/Taxonomy/Biogeography; Plants (botany); Pollination; Research Article; Seed dimorphism; Seeds; Trifolium; Trifolium argentinense
• ISSN: 0925-9864; 1573-5109
• DOI: 10.1007/s10722-009-9508-1

Amphicarpy, a specialized form of dimorphism where fruits and seeds are formed in underground and aerial flowers, has been reported in only ca. 50 flowering plants. Trifolium argentinense Speg. is an amphicarpic legume species that occurs in native pastures of Southern Brazil. Data on seed dimorphism, chromosome number and karyotype of the species are presented for the first time. T. argentinense is diploid, with 2n = 2x = 16. Chromosome size range from ca. 2.8 to 1.6 μm, the karyotypic formula is 3 metacentric + 1 satellite-bearing metacentric + 3 acrocentric + 1 subacrocentric and a TCL (total complement length) of 18.10 μm. All the subterranean, but around 70% of the aerial legumes formed seeds. Subterranean seeds were larger and heavier (2.1 mm and 0.0029 g, respectively) than the aerial ones (1.8 mm and 0.0016 g, respectively). As a follow up to this work, we plan to characterize aerial and subterranean-seed-derived plants regarding aspects such as growing rate, height, leaf size and forage production, as well as to determine the exact mode of reproduction of T. argentinense by pollination experiments and the use of molecular markers.